1. Field of the Invention
This invention relates to a removable, reusable thermal insert designed to impart cooling properties to and is universally applicable to many standard beverage containers such as common sport water bottles.
2. Description of Prior Art
Outdoors and fitness enthusiasts commonly use plastic molded beverage containers to carry water or other soft drinks to refresh thirst and replenish fluids during activities such as bicycling, hiking, walking, running or aerobic exercise. Many users find cool fluids more refreshing. Recent exercise physiology studies also indicate that cool fluids are absorbed more readily by the body and may help control thermal regulatory activity.
Common approaches to maintain cool temperature in contained fluids include external insulation such as cloth, foam, neoprene or other like materials. Another method to keep fluids cool is to surround the container with an enclosure filled with a fluid or material which can be frozen such as disclosed in U.S. Pat. Nos. 4,183,226, 4,338,795, 4,383,422, and 4,932,225 (reference U.S. Pat. No. 5,129,238). These designs make it difficult to carry the container during outdoor activities and do not fit many standard sport water bottles or bicycle water bottle cages.
U.S. Pat. No. 4,741,176 describes another approach comprising a sealed container incorporating a tube filled with a refrigerant material which imparts cooling properties to the fluid in the container. Similar containers are disclosed in U.S. Pat. Nos. 4,981,022 and 5,129,238. In the invention described in U.S. Pat. No. 4,981,022 a plastic tube filled with a non-toxic thermal cooling material is sealed and welded to the base of the inside of the beverage container. This requires the user to purchase the entire bottle/cooler system. In addition, the entire bottle/cooler system must be placed in a freezer to freeze the coolant. This requires space and puts the bottle through numerous freeze/thaw cycles which reduce the life of the container. In the latter invention, a refrigerant material is enclosed in a plastic tube. The tube is designed with threads to fit into the cap of the container. The tube can be removed from the container and cap, can be frozen, then can be replaced in the cap and container to impart cooling properties to the beverage in the container. Again, the customer is limited to using the bottle designed by the manufacturer. In addition, the container does not fit well in many common bike bottle cages. And the tube is not designed to fit in many commonly used sport bottles. Assembly and disassembly of the bottle/cap/tube system is cumbersome and requires multiple steps to accomplish. In many of the inventions an aqueous mixture of water, urea and propylene glycol or water and propylene glycol is used as the refrigerant solution.
Most outdoors, bicycle and fitness enthusiasts already own multiple sport water bottles. A universally applicable removable, reusable thermal insert is needed which can be purchased independent of a proprietary container system is an improved method to cool beverages in containers for extended periods of time. The insert should be designed to fit snugly in the bottle to minimize movement and raffling during use. The insert should also provide cooling while minimizing volume of fluid displaced.